Treatment methods using atoxic neurotoxin derivatives

ABSTRACT

The present invention relates to a treatment method. This method involves contacting a subject with an isolated, physiologically active, atoxic derivative of a Clostridial neurotoxin. Contacting is carried out to treat the subject. The derivative of a Clostridial neurotoxin does not possess a cargo attachment peptide sequence at its N-terminus.

This application is a continuation of U.S. patent application Ser. No.14/166,434 filed Jan. 28, 2014, which claims the benefit of U.S.Provisional Patent Application Ser. No. 61/757,478, filed Jan. 28, 2013,which is hereby incorporated by reference in its entirety.

The subject matter of this application was made with support from theUnited States Government under National Institutes of Health grant RO1A1093504. The United States Government has certain rights.

FIELD OF THE INVENTION

This invention relates to treatment methods using atoxic neurotoxinderivatives.

BACKGROUND OF THE INVENTION

The Clostridial neurotoxins are a family of structurally similarproteins that target the neuronal machinery for synaptic vesicleexocytosis. Produced by anaerobic bacteria of the Clostridium genus,botulinum neurotoxins (“BoNT”s, seven immunologically distinct subtypes,A-G) and Tetanus neurotoxin (“TeNT”) are the most poisonous substancesknown on a per-weight basis, with an LD₅₀ in the range of 0.5-2.5 ng/kgwhen administered by intravenous or intramuscular routes (NationalInstitute of Occupational Safety and Health, “Registry of Toxic Effectsof Chemical Substances (R-TECS),” Cincinnati, Ohio: National Instituteof Occupational Safety and Health (1996)). BoNTs target cholinergicnerves at their neuromuscular j unction, inhibiting acetylcholinerelease and causing peripheral neuromuscular blockade (Simpson,“Identification of the Major Steps in Botulinum Toxin Action,” Annu.Rev. Pharmacol. Toxicol. 44:167-193 (2004)).

A genetic engineering platform that enables rational design oftherapeutic agents based on Clostridial toxin genes was described inU.S. Pat. No. 7,785,606 to Ichtchenko and Band. The genetic engineeringscheme was based on a two-step approach. Gene constructs, expressionsystems, and purification schemes were designed that producephysiologically active, recombinant Clostridial neurotoxin derivatives.The recombinant toxin derivatives retained structural features importantfor developing therapeutic candidates, or useful biologic reagents.Using the genetic constructs and expression systems developed by thisparadigm, selective point mutations were then introduced to createrecombinant atoxic Clostridial neurotoxin derivatives.

Treatment methods that involve contacting a patient with isolated,physiologically active, toxic, Clostridial neurotoxin derivatives havebeen described in U.S. Pat. No. 7,785,606 to Band and Ichtchenko. Also,isolated, physiologically active, toxic and atoxic Clostridium botulinumneurotoxin derivatives that have an S6 peptide sequence fused to theN-terminus of the proteins to enable site-specific attachment of cargousing Sfp phosphopantetheinyl transferase have been described assuitable for treatment (U.S. Patent Application Publication No.2011/0206616 to Ichtchenko and Band). However, methods that involvetreatment with an atoxic derivative of a Clostridial neurotoxin lackinga cargo attachment sequence at its N-terminus, and having a much higherLD₅₀ than a toxic derivative of a Clostridial neurotoxin or a wild typeClostridial neurotoxin, have not been described.

The present invention is directed to overcoming this and otherlimitations in the art.

SUMMARY OF THE INVENTION

The present invention relates to a treatment method. This methodinvolves contacting a subject with an isolated, physiologically active,atoxic derivative of a Clostridial neurotoxin, said contacting beingcarried out to treat the subject, with the proviso that the neurotoxinderivative does not possess a cargo attachment peptide sequence at itsN-terminus.

Genetic constructs and expression systems described herein are shown toproduce a family of recombinant BoNT derivatives, with conformationaland trafficking properties similar to the wild type BoNT toxins. Thesederivatives of Clostridial neurotoxins can be produced in toxic forms,having a toxicity comparable to that of the wild type toxin, or withmutations that reduce the metalloprotease activity responsible fortoxicity (i.e., atoxic derivatives). The LD₅₀ of the atoxic neurotoxinderivatives is much higher than that of the wild type toxin.

As described herein, the atoxic neurotoxin derivatives (see U.S. Pat.No. 7,785,606 to Ichtchenko et al., which is hereby incorporated byreference in its entirety) unexpectedly have in vivo activity similar tothe wild type neurotoxins used for pharmaceutical purposes. Yet, atoxicneurotoxin derivatives described herein offer significant treatmentbenefits over current pharmaceutical preparations of wild typeneurotoxins produced from cultures. In particular, the atoxicderivatives described herein are safer, providing distinct advantagesfor medical uses and production/manufacturing. The improved therapeuticindex will enable application to conditions where the toxicity of wildtype neurotoxins limit their use because of safety concerns.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-C are a comparative alignment of amino acid sequences of sevenwild type botulinum neurotoxin serotypes, including Clostridiumbotulinum serotype A (wt BoNT A) (SEQ ID NO:1), Clostridium botulinumserotype B (wt BoNT B) (SEQ ID NO:2), Clostridium botulinum serotype C(wt BoNT C) (SEQ ID NO:3), Clostridium botulinum serotype D (wt BoNT D)(SEQ ID NO:4), Clostridium botulinum serotype E (wt BoNT E) (SEQ IDNO:5), Clostridium botulinum serotype F (wt BoNT F) (SEQ ID NO:6), andClostridium botulinum serotype G (wt BoNT G) (SEQ ID NO:7). Gaps havebeen introduced to maximize homology. Amino acids identical in >50% ofcompared sequences are shown in black boxes. Amino acids constitutingthe active site of the catalytic domain of metalloprotease are marked bystars. Disulfide bridge between neurotoxin cysteine residues of thelight and heavy chain are shown as a long horizontal bracket. The aminoacid residues constituting the minimal catalytic domain of the lightchain are hatched. The first amino acid of the C-terminal part of theprotein heavy chain (N872 for BoNT A), is shown with a white arrow, asis the first amino acid considered to constitute the receptor-bindingdomain. Amino acids absent in the mature dichain BoNT A molecule alongwith the aligned amino acids of the other BoNT serotypes are boxed. Awhite arrow is also positioned at the first amino acid of theneurotoxins' light chain.

FIG. 2 is a photograph showing the results of in vivo studies performedby intramuscular injection into the lateral gastrocnemius with 0.5μg/mouse of BoNT A/ad-0 (experimental) in 3 μl of 0.9% NaCl or byinjecting 3 μl of 0.9% of NaCl without BoNT A/ad-0 (control). Muscleparalysis and digital abduction was recorded 48 hours after. The twoupper panel photographs show control mice, with the arrow in the upperright photograph indicating the site of injection. The three lower panelphotographs show experimental mice. Digital abduction muscle paralysiswas only observed in mice injected with BoNT A/ad-O. Experimental, n=10.Control, n=5. Representative results are shown in the photographs in thethree bottom panels.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a treatment method. This methodinvolves contacting a subject with an isolated, physiologically active,atoxic derivative of a Clostridial neurotoxin, said contacting beingcarried out to treat the subject, with the proviso that the neurotoxinderivative does not possess a cargo attachment peptide sequence at itsN-terminus.

According to one embodiment, the derivative of a Clostridial neurotoxinof the present invention is a derivative of a Clostridium botulinumneurotoxin. Clostridium botulinum has multiple serotypes (A-G). Suitablederivatives of a Clostridial neurotoxin may be derivatives of any of theClostridium botulinum serotypes. In addition, suitable derivatives of aClostridial neurotoxin of the present invention may be derivatives ofmore than one Clostridium botulinum serotype. For example, it may bedesirable to have a derivative of a Clostridial neurotoxin constructedof a light chain (LC) region from one Clostridium botulinum serotype(e.g., serotype A, BoNT A) and a heavy chain (HC) region from anotherClostridium botulinum serotype (e.g., serotype B, BoNT B). Also,suitable derivatives of a Clostridial neurotoxin of the presentinvention include chimeras using other receptor ligands, e.g., epidermalgrowth factor (“EGF”) for LC delivery to cancer cells (see U.S. PatentApplication Publication no. 2012/0064059 to Foster et al., which ishereby incorporated by reference in its entirety).

By “derivative” it is meant that the Clostridial neurotoxin issubstantially similar to the wild type toxin, but has been modifiedslightly as described herein. For example, derivatives includeClostridial neurotoxins that are at least 60%, 70%, 80%, 85%, 90%, 95%,96%, 97%, 98%, or 99% identical to a wild type neurotoxin.

Isolated derivatives of a Clostridial neurotoxin are physiologicallyactive. This physiological activity includes, but is not limited to,toxin immunogenicity, trans- and intra-cellular trafficking, cellrecognition and targeting, and paralytic activity. In one embodiment,the derivative of a Clostridal neurotoxin is a derivative of afull-length Clostridial neurotoxin.

The atoxic derivative of a Clostridial neurotoxin designated hereinusing the “ad-0” designation, does not have an S6 peptide sequence fusedto the N-terminus of the neurotoxin derivative, as described in U.S.Patent Application Publication No. 2011/0206616 to Icthtchenko and Band,which is hereby incorporated by reference in its entirety.

The mechanism of cellular binding and internalization of Clostridialneurotoxins is still not completely understood. The C-terminal portionof the heavy chain of all Clostridial neurotoxins binds to gangliosides(sialic acid-containing glycolipids), with a preference for gangliosidesof the G_(ib) series (Montecucco et al., “Structure and Function ofTetanus and Botulinum Neurotoxins,” Q. Rev. Biophys. 28:423-472 (1995);Montecucco, “How Do Tetanus and Botulinum Toxins Bind to NeuronalMembranes?” TIBS 11:314-317 (1986); and Van Heyningen et al., “TheFixation of Tetanus Toxin by Ganglioside,” J. Gen. Microbiol. 24:107-119(1961), which are hereby incorporated by reference in their entirety).The sequence responsible for ganglioside binding has been identified forthe structurally similar TeNT molecule, and is located within the 34C-terminal amino acid residues of its heavy chain. BoNT A, BoNT B, BoNTC, BoNT E, and BoNT F share a high degree of homology with TeNT in thisregion (FIG. 1) (Shapiro et al., “Identification of a GangliosideRecognition Domain of Tetanus Toxin Using a Novel GangliosidePhotoaffinity Ligand,” J. Biol. Chem. 272:30380-30386 (1997), which ishereby incorporated by reference in its entirety). Multiple types ofevidence suggest the existence of at least one additional componentinvolved in the binding of Clostridial neurotoxins to neuronal membranes(Montecucco et al., “Structure and Function of Tetanus and BotulinumNeurotoxins,” Q. Rev. Biophys. 28:423-472 (1995); Montecucco, “How DoTetanus and Botulinum Toxins Bind to Neuronal Membranes?” TIBS11:314-317 (1986), which are hereby incorporated by reference in theirentirety). In two reports (Nishiki et al., “The High-Affinity Binding ofClostridium Botulinum Type B Neurotoxin to Synaptotagmin II Associatedwith Gangliosides G_(T1b)/G_(D1a) ,” FEBS Lett 378:253-257 (1996); Donget al., “Synaptotagmins I and II Mediate Entry of Botulinum Neurotoxin Binto Cells,” J. Cell Biol. 162:1293-1303 (2003), which are herebyincorporated by reference in their entirety), synaptotagmins wereidentified as possible candidates for the auxiliary BoNT B receptor, andsynaptotagmins I and II were implicated as neuronal receptors for BoNT G(Rummel et al., “Synaptotagmins I and II Act as Nerve Cell Receptors forBotulinum Neurotoxin G,” J. Biol. Chem. 279:30865-30870 (2004), which ishereby incorporated by reference in its entirety). Dong et al., “SV2 isthe Protein Receptor for Botulinum Neurotoxin A,” Science 312:592-596(2006), which is hereby incorporated by reference in its entirety,showed that BoNT A enters neurons by binding to the synaptic vesicleprotein SV2 (isoforms A, B, and C). However, despite the structuralsimilarity in the putative receptor-binding domain of Clostridialneurotoxins, other toxin subtypes show no affinity for SV2 and insteadmay target synaptotagmins or synaptotagmin-related molecules. Lipidrafts (Herreros et al., “Lipid Rafts Act as Specialized Domains forTetanus Toxin Binding and Internalization into Neurons,” Mol. Biol. Cell12:2947-2960 (2001), which is hereby incorporated by reference in itsentirety) have been implicated as a specialized domain involved in TeNTbinding and internalization into neurons, but these domains are widelydistributed on multiple cell types, and therefore cannot simply explainthe high specificity of the toxins for neurons.

Clostridial neurotoxins are internalized through the presynapticmembrane by an energy-dependent mechanism (Montecucco et al., “Structureand Function of Tetanus and Botulinum Neurotoxins,” Q. Rev. Biophys.28:423-472 (1995); Matteoli et al., “Synaptic Vesicle EndocytosisMediates the Entry of Tetanus Neurotoxin into Hippocampal Neurons,”Proc. Natl. Acad. Sci. USA 93:13310-13315 (1996); and Mukherjee et al.,“Endocytosis,” Physiol. Rev. 77:759-803 (1997), which are herebyincorporated by reference in their entirety), and rapidly appear invesicles where they are at least partially protected from degradation(Dolly et al., “Acceptors for Botulinum Neurotoxin Reside on Motor NerveTerminals and Mediate Its Internalization,” Nature 307:457-460 (1984);Critchley et al., “Fate of Tetanus Toxin Bound to the Surface of PrimaryNeurons in Culture: Evidence for Rapid Internalization,” J. Cell Biol.100:1499-1507 (1985), which are hereby incorporated by reference intheir entirety). The BoNT complex of light and heavy chains interactswith the endocytic vesicle membrane in a chaperone-like way, preventingaggregation and facilitating translocation of the light chain in afashion similar to the protein conducting/translocating channels ofsmooth ER, mitochondria, and chloroplasts (Koriazova et al.,“Translocation of Botulinum Neurotoxin Light Chain Protease through theHeavy Chain Channel,” Nat. Struct. Biol. 10:13-18 (2003), which ishereby incorporated by reference in its entirety). Acidification of theendosome is believed to induce pore formation, which allowstranslocation of the light chain to the cytosol upon reduction of theinterchain disulfide bond (Hoch et al., “Channels Formed by Botulinum,Tetanus, and Diphtheria Toxins in Planar Lipid Bilayers: Relevance toTranslocation of Proteins Across Membranes,” Proc. Natl. Acad. Sci. USA82:1692-1696 (1985), which is hereby incorporated by reference in itsentirety). Within the cytosol, the light chain displays azinc-endopeptidase activity specific for protein components of thesynaptic vesicle exocytosis apparatus. TeNT and BoNT B, BoNT D, BoNT F,and BoNT G recognize VAMP/synaptobrevin. This integral protein of thesynaptic vesicle membrane is cleaved at a single peptide bond, whichdiffers for each neurotoxin. BoNT A, BoNT C, and BoNT E recognize andcleave SNAP-25, a protein of the presynaptic membrane, at differentsites within the carboxyl terminus segment. BoNT C also cleavessyntaxin, another protein of the nerve terminal plasmalemma (Montecuccoet al., “Structure and Function of Tetanus and Botulinum Neurotoxins,”Q. Rev. Biophys. 28:423-472 (1995); Sutton et al., “Crystal Structure ofa SNARE Complex Involved in Synaptic Exocytosis at 2.4 Å Resolution,”Nature 395:347-353 (1998), which are hereby incorporated by reference intheir entirety). The cleavage of such components of the synaptic releasemachinery results in inhibition of acetylcholine release in motorneurons, ultimately leading to neuromuscular paralysis.

The isolated derivative of a Clostridial neurotoxin employed in themethod of the present invention is physiologically active and atoxic.The endopeptidase activity responsible for Clostridial neurotoxintoxicity is believed to be associated with the presence of a HExxHxxH(SEQ ID NO:8) motif in the light chain, characteristic ofmetalloproteases (FIGS. 1A-C). Mutagenesis of BoNT A light chain,followed by microinjection of the corresponding mRNA into presynapticcholinergic neurons of Aplysia californica, allowed the minimalessential domain responsible for toxicity to be identified (Kurazono etal., “Minimal Essential Domains Specifying Toxicity of the Light Chainsof Tetanus Toxin and Botulinum Neurotoxin Type A,” J. Biol. Chem.267:14721-14729 (1992), which is hereby incorporated by reference in itsentirety). Site-directed mutagenesis of BoNT A light chain pinpointedthe amino acid residues involved in Zn²⁺ coordination, and formation ofthe active metalloendoprotease core which cleaves SNAP-25 (Rigoni etal., “Site-Directed Mutagenesis Identifies Active-Site Residues of theLight Chain of Botulinum Neurotoxin Type A,” Biochem. Biophys. Res.Commun. 288:1231-1237 (2001), which is hereby incorporated by referencein its entirety). The three-dimensional structures of Clostridialneurotoxins and their derivatives confirmed the mutagenesis results, anddetailed the spatial organization of the protein domains. For the BoNT Aholotoxin, crystal structure was obtained to a resolution of 3.3 Å (Lacyet al., “Crystal Structure of Botulinum Neurotoxin Type A andImplications for Toxicity,” Nat. Struct. Biol. 5:898-902 (1998), whichis hereby incorporated by reference in its entirety). The BoNT Bholotoxin crystal structure was determined at 1.8 and 2.6 Å resolution(Swaminathan et al., “Structural Analysis of the Catalytic and BindingSites of Clostridium Botulinum Neurotoxin B,” Nat. Struct. Biol.7:693-699 (2000), which is hereby incorporated by reference in itsentirety). Recently, a crystal structure for BoNT E catalytic domain wasdetermined to 2.1 Å resolution (Agarwal et al., “Structural Analysis ofBotulinum Neurotoxin Type E Catalytic Domain and Its Mutant Glu212>GlnReveals the Pivotal Role of the Glu212 Carboxylate in the CatalyticPathway,” Biochemistry 43:6637-6644 (2004), which is hereby incorporatedby reference in its entirety). The later study provided multipleinteresting structural details, and helps explain the complete loss ofmetalloendoproteolytic activity in the BoNT E LC E212>Q mutant. Theavailability of this detailed information on the relationship betweenthe amino acid sequence and biological activities of Clostridial toxinsenables the design of modified toxin genes with properties specificallyaltered for therapeutic goals.

Thus, in one embodiment, the physiologically active and atoxicderivative of a Clostridial neurotoxin has a metalloprotease disablingmutation. Specific metalloprotease disabling mutations are described inU.S. Pat. No. 7,785,606 to Ichthchenko and Band, which is herebyincorporated by reference in its entirety. Additional point mutationscan be introduced to further modify the characteristics of the atoxicderivative, some of which are also described in U.S. Pat. No. 7,785,606to Ichthchenko and Band, which is hereby incorporated by reference inits entirety.

The physiologically active and atoxic derivative of a Clostridialneurotoxin may also have a non-native motif (e.g., a SNARE motif) in thelight chain region that is capable of inactivating light chainmetalloprotease activity in a toxic Clostridial neurotoxin, or otherwisemodifying the behavior of the derivative. The sequences of ninenon-native motifs that may be substituted for alpha-helix domains aredescribed in U.S. Pat. No. 7,785,606 to Ichtchenko and Band, which ishereby incorporated by reference in its entirety. Atoxic derivativesthat incorporate sequences to target other cellular receptors are alsopossible (e.g., EGF or cancer cells) (see U.S. Patent ApplicationPublication No. 2012/0064059 to Foster et al., which is herebyincorporated by reference in its entirety).

In one embodiment, the physiologically active and atoxic derivative of aClostridial neurotoxin has an LD₅₀ that is at least 1,000; 2,000; 5,000;7,000; 9,000; 10,000; 20,000; 30,000; 40,000; 50,000; 60,000; 70,000;80,000; 90,000; 100,000; or 500,000-fold higher than the LD₅₀ of wildtype Clostridial neurotoxin. The particular mode of administration mayaffect the LD₅₀ of the derivative of a Clostridial neurotoxin.

In one embodiment, the derivative of a Clostridal neurotoxin of thepresent invention is produced by cleaving a propeptide. The propeptideis cleaved at the highly specific protease cleavage site to form a lightand heavy chain, with molecular weights of approximately 50 kD and 100kD, respectively. The light and heavy chain regions are linked by adisulfide bond.

In one embodiment, the propeptide is contacted with a highly specificprotease (e.g., enterokinase or TEV protease) under conditions effectiveto enable cleavage at the intermediate region of the propeptide of thepresent invention. Preferably, the expressed propeptide has one or moredisulfide bridges.

As discussed infra, Clostridial neurotoxins and their derivativesdescribed herein are synthesized as single chain propeptides which arelater activated by a specific proteolysis cleavage event, generating adimer joined by a disulfide bond. These structural features can beillustrated using BoNT A as an example, and are generally applicable toall Clostridium botulinum serotypes. The mature BoNT A is composed ofthree functional domains of Mr 50,000, where the catalytic functionresponsible for toxicity is confined to the light chain (residues1-437), the translocation activity is associated with the N-terminalhalf of the heavy chain (residues 448-872), and cell binding isassociated with its C-terminal half (residues 873-1,295) (Johnson,“Clostridial Toxins as Therapeutic Agents: Benefits of Nature's MostToxic Proteins,” Annu. Rev. Microbiol. 53:551-575 (1999); Montecucco etal., “Structure and Function of Tetanus and Botulinum Neurotoxins,” Q.Rev. Biophys. 28:423-472 (1995), which are hereby incorporated byreference in their entirety).

Optimized expression and recovery of recombinant neurotoxins for BoNTserotypes in a native and physiologically active state is achieved bythe introduction of one or more alterations to the nucleotide sequencesencoding the BoNT propeptides, as discussed infra. These mutations aredesigned to maximize yield of recombinant derivatives of a Clostridialneurotoxin, while retaining the native toxins' structure and biologicalactivity.

Common structural features of the wild-type Clostridium botulinumneurotoxin propeptides are shown in FIGS. 1A-C. These structuralfeatures are illustrated using wt BoNT A propeptide as an example, andare generalized among all Clostridium botulinum serotypes. wt BoNT Apropeptide has two chains, a light chain (“LC”) of Mr˜50,000 and a heavychain (“HC”) of Mr˜100,000, linked by a disulfide bond between Cys₄₂₉and Cys₄₅₃. As illustrated in FIGS. 1A-C, all seven BoNT serotypepropeptides have a light chain region and a heavy chain region linked bya disulfide bond. Two essential Cys residues, one adjacent to theC-terminus of the light chain, and a second adjacent to the N-terminusof the heavy chain are present in all seven BoNT serotypes. These twoCys residues form the single disulfide bond holding the HC and LCpolypeptides together in the mature neurotoxin. This disulfide bondenables the mature neurotoxin to accomplish its native physiologicalactivities by permitting the HC and LC to carry out their respectivebiological roles in concert. The disulfide bond between HC and LCpolypeptides in all seven serotypes is illustrated in FIG. 1A by thesolid line joining the involved Cys residues. The outlined box in FIG.1A illustrates the intermediate region defined by amino acid residuesLys₄₃₈-Lys₄₄₈ of wt BoNT A. This intermediate region identifies theamino acids eliminated during maturation of wt BoNT A, and believed tobe excised by a protease endogenous to the host microorganism. Thiscleavage event, described infra, generates the biologically active BoNTHC-LC dimer. The outlined amino acid residues in FIGS. 1A-C,representing amino acid residues approximately in the 420 to 450 rangefor all seven BoNT serotypes, can be considered as a region“non-essential” to the toxins' physiological activity and, therefore,represents targets for directed mutagenesis in all seven BoNT serotypes.

All seven wt BoNT serotypes referred to herein contain Lys or Argresidues in the intermediate region defined by the box in FIG. 1A, whichmake the propeptides susceptible to activation by trypsin. Native BoNT Apropeptide recovered from young bacterial cultures can be activated bytrypsinolysis, with production of intact, S—S bound light and heavychain. Though multiple additional trypsin-susceptible sites are presentin the propeptides, they are resistant to proteolysis due to theirspatial positions within the native toxin molecule (Dekleva et al.,“Nicking of Single Chain Clostridium botulinum Type A Neurotoxin by anEndogenous Protease,” Biochem. Biophys. Res. Commun. 162:767-772 (1989);Lacy et al., “Crystal Structure of Botulinum Neurotoxin Type A andImplications for Toxicity,” Nat. Struct. Biol. 5:898-902 (1998), whichare hereby incorporated by reference in their entirety). A second sitein the native propeptide of several BoNT serotypes can be susceptible totrypsin cleavage when subjected to higher enzyme concentrations orincubation times (Chaddock et al., “Expression and Purification ofCatalytically Active, Non-Toxic Endopeptidase Derivatives of Clostridiumbotulinum Toxin Type A,” Protein Expr. Purif. 25:219-228 (2002), whichis hereby incorporated by reference in its entirety). Thistrypsin-susceptible site is located in the region adjacent to the toxinreceptor binding domain. This region of the HC peptide is found to beexposed to solvent in BoNT serotypes for which information is availableon their 3-D crystal structure (Lacy et al., “Crystal Structure ofBotulinum Neurotoxin Type A and Implications for Toxicity,” Nat. Struct.Biol. 5:898-902 (1998); Swaminathan et al., “Structural Analysis of theCatalytic and Binding Sites of Clostridium botulinum Neurotoxin B,” Nat.Struct. Biol. 7:693-699 (2000), which are hereby incorporated byreference in their entirety).

In one embodiment, the propeptide has an intermediate region connectingthe light and heavy chain regions which has a highly specific proteasecleavage site and no low-specificity protease cleavage sites. Forpurposes of the present invention, a highly specific protease cleavagesite has three or more specific adjacent amino acid residues that arerecognized by the highly specific protease in order to permit cleavage(e.g., an enterokinase cleavage site or a TEV recognition sequence). Incontrast, a low-specificity protease cleavage site has two or lessadjacent amino acid residues that are recognized by a protease in orderto enable cleavage (e.g., a trypsin cleavage site).

In all seven BoNT serotypes, the amino acid preceding the N-terminus ofthe heavy chain is a Lys or Arg residue which is susceptible toproteolysis with trypsin. This trypsin-susceptible site can be replacedwith a five amino acid enterokinase cleavage site (i.e., DDDDK (SEQ IDNO:9)) upstream of the heavy chain's N-terminus. Alternatively, thetrypsin-susceptible site can be replaced with a tobacco etch virusprotease recognition (“TEV”) sequence. Use of a TEV sequence enables aone-step heterodimer-forming cleavage event. See U.S. Patent ApplicationPublication No. 2011/0206616 to Ichtchenko et al., which is herebyincorporated by reference in its entirety. Either of these modificationsenables standardization activation with specific enzymes. In serotypes Aand C, additional Lys residues within this region may be mutated toeither Gln or His, thereby eliminating additional trypsin-susceptiblesites. Trypsin-susceptible recognition sequences also occur upstream ofthe heavy chain's receptor-binding domain in serotypes A, E, and F. Thisregion's susceptibility to proteolysis is consistent with its exposureto solvent in the toxin's 3-D structure, as shown by X-raycrystallography analysis. Therefore, in serotypes A, E, and F, thesusceptible residues are modified to Asn. These modifications enablestandardization activation with either enterokinase or TEV.

Signal peptides and N-terminal affinity tags are also preferablyintroduced, as required, to enable secretion and recovery and toeliminate truncated variants. The affinity tags can be separated fromthe N-terminus and C-terminus of the neurotoxin by cleavage using thesame specific proteases used to cleave the heavy and light chain.

In one embodiment, the derivative of a Clostridial neurotoxin is from apropeptide that has a metalloprotease disabling mutation. The amino acidresidues constituting the minimal catalytic domain of the light chain ofthe propeptide are illustrated in FIG. 1A by hatching. Specific aminoacid residues constituting the active site of the catalytic domain ofthe metalloprotease are marked by stars in FIG. 1A.

A variety of Clostridial neurotoxin propeptides with light chain regionscontaining non-native motifs (e.g., SNARE motif peptides) in place ofsurface alpha-helix domains can be created. These non-native motifbearing propeptides are generated by altering the nucleotide sequencesof nucleic acids encoding the propeptides.

In one embodiment, the light and heavy chains of the propeptide are nottruncated.

In one embodiment, the propeptide further comprises a signal peptidecoupled to the light chain region, where the signal peptide is suitableto permit secreation of the propeptide from a eukaryotic cell to amedium. Suitable signal peptides are described in U.S. Pat. No.7,785,606 to Ichtchenko and Band, which is hereby incorporated byreference in its entirety. A suitable signal peptide is a gp64 signalpeptide.

The propeptide may also have an affinity tag located between the signalpeptide and the light chain region and/or at the C-terminus of thepropeptide. A suitable affinity tag is the hexahistidine affinity tagMPMLSAIVLYVLLAAAAHSAFAAMVHHHHHHSAS . . . (SEQ ID NO:10). Structuralvariations of suitable Clostridial neurotoxin propeptides that possess acargo attachment peptide sequence are described in U.S. PatentApplication Publication No. 2011/0206616 to Ichtchenko and Band, whichis hereby incorporated by reference in its entirety. Propeptides thatencode atoxic derivatives of a Clostridial neurotoxin suitable for usein the method of the present invention may have any of the structuralfeatures of the propeptides described in U.S. Patent ApplicationPublication No. 2011/0206616 to Ichtchenko and Band, which is herebyincorporated by reference in its entirety, other than the cargoattachment peptide sequence at the N-terminus. As described in U.S.Patent Application Publication No. 2011/0206616 to Ichtchenko and Band,which is hereby incorporated by reference in its entirety, a singleprotease cleavage step can be used for activation and removal ofaffinity tags.

Isolated nucleic acid molecules that encode atoxic derivatives of aClostridial neurotoxin suitable for use in the method of the presentinvention are described in U.S. Pat. No. 7,785,606 to Ichtchenko andBand, which is hereby incorporated by reference in its entirety.

In one embodiment, the nucleic acid molecule has a metalloproteasedisabling mutation, as described supra.

In one embodiment, the derivative of a Clostridal neurotoxin is arecombinant protein. Expression systems having a nucleic acid moleculeencoding an isolated, physiologically active, atoxic derivative of aClostridial neurotoxin in a heterologous vector, and host cells having aheterologous nucleic acid molecule encoding an isolated, physiologicallyactive, atoxic derivative of a Clostridial neurotoxin are described inU.S. Pat. No. 7,785,606 to Ichtchenko and Band, which is herebyincorporated by reference in its entirety.

Expressing a recombinant, physiologically active, atoxic derivative of aClostridial neurotoxin is carried out by providing a nucleic acidconstruct having a nucleic acid molecule encoding a propeptide asdescribed herein. The nucleic acid construct has a heterologous promoteroperably linked to the nucleic acid molecule and a 3′ regulatory regionoperably linked to the nucleic acid molecule. The nucleic acid constructis then introduced into a host cell under conditions effective toexpress the physiologically active, atoxic derivative of a Clostridialneurotoxin.

In one embodiment, the expressed neurotoxin derivative is contacted witha highly specific protease under conditions effective to effect cleavageat the intermediate region. Preferably, the intermediate region of thepropeptide is not cleaved by proteases endogenous to the expressionsystem or the host cell.

Expression of a derivative of a Clostridial neurotoxin can be carriedout by introducing a nucleic acid molecule encoding a propeptide into anexpression system of choice using conventional recombinant technology.Generally, this involves inserting the nucleic acid molecule into anexpression system to which the molecule is heterologous (i.e., notnormally present). The introduction of a particular foreign or nativegene into a mammalian host is facilitated by first introducing the genesequence into a suitable nucleic acid vector. “Vector” is used herein tomean any genetic element, such as a plasmid, phage, transposon, cosmid,chromosome, virus, virion, etc., which is capable of replication whenassociated with the proper control elements and which is capable oftransferring gene sequences between cells. Thus, the term includescloning and expression vectors, as well as viral vectors. Theheterologous nucleic acid molecule is inserted into the expressionsystem or vector in proper sense (5′→3′) orientation and correct readingframe. The vector contains the necessary elements for the transcriptionand translation of the inserted Clostridial neurotoxin propeptide-codingsequences.

U.S. Pat. No. 4,237,224 to Cohen and Boyer, which is hereby incorporatedby reference in its entirety, describes the production of expressionsystems in the form of recombinant plasmids using restriction enzymecleavage and ligation with DNA ligase. These recombinant plasmids arethen introduced by means of transformation and replicated in unicellularcultures including prokaryotic organisms and eukaryotic cells grown inculture.

Recombinant genes may also be introduced into viruses, includingvaccinia virus, adenovirus, and retroviruses, including lentivirus.Recombinant viruses can be generated by transfection of plasmids intocells infected with virus.

Suitable vectors include, but are not limited to, the following viralvectors such as lambda vector system gt11, gt WES.tB, Charon 4, andplasmid vectors such as pBR322, pBR325, pACYC177, pACYC184, pUC8, pUC9,pUC18, pUC19, pLG339, pR290, pKC37, pKC101, SV 40, pBluescript II SK+/−or KS+/−(see “Stratagene Cloning Systems” Catalog (1993) fromStratagene, La Jolla, Calif., which is hereby incorporated by referencein its entirety), pQE, pIH821, pGEX, pFastBac series (Invitrogen), pETseries (see F. W. Studier et. al., “Use of T7 RNA Polymerase to DirectExpression of Cloned Genes,” Gene Expression Technology Vol. 185 (1990),which is hereby incorporated by reference in its entirety), and anyderivatives thereof. Recombinant molecules can be introduced into cellsvia transformation, particularly transduction, conjugation,mobilization, or electroporation. The DNA sequences are cloned into thevector using standard cloning procedures in the art, as described bySambrook et al., Molecular Cloning: A Laboratory Manual, Cold SpringsLaboratory, Cold Springs Harbor, N.Y. (1989), which is herebyincorporated by reference in its entirety.

A variety of host-vector systems may be utilized to express thepropeptide-encoding sequence in a cell. Primarily, the vector systemmust be compatible with the host cell used. Host-vector systems includebut are not limited to the following: bacteria transformed withbacteriophage DNA, plasmid DNA, or cosmid DNA; microorganisms such asyeast containing yeast vectors; mammalian cell systems infected withvirus (e.g., vaccinia virus, adenovirus, etc.); insect cell systemsinfected with virus (e.g., baculovirus); and plant cells infected bybacteria. The expression elements of these vectors vary in theirstrength and specificities. Depending upon the host-vector systemutilized, any one of a number of suitable transcription and translationelements can be used.

Different genetic signals and processing events control many levels ofgene expression (e.g., DNA transcription and messenger RNA (“mRNA”)translation).

Transcription of DNA is dependent upon the presence of a promoter whichis a DNA sequence that directs the binding of RNA polymerase and therebypromotes mRNA synthesis. The DNA sequences of eukaryotic promotersdiffer from those of prokaryotic promoters. Furthermore, eukaryoticpromoters and accompanying genetic signals may not be recognized in ormay not function in a prokaryotic system, and, further, prokaryoticpromoters are not recognized and do not function in eukaryotic cells.

Similarly, translation of mRNA in prokaryotes depends upon the presenceof the proper prokaryotic signals which differ from those of eukaryotes.Efficient translation of mRNA in prokaryotes requires a ribosome bindingsite called the Shine-Dalgarno (“SD”) sequence on the mRNA. Thissequence is a short nucleotide sequence of mRNA that is located beforethe start codon, usually AUG, which encodes the amino-terminalmethionine of the protein. The SD sequences are complementary to the3′-end of the 16S rRNA (ribosomal RNA) and probably promote binding ofmRNA to ribosomes by duplexing with the rRNA to allow correctpositioning of the ribosome. For a review on maximizing gene expressionsee Roberts and Lauer, Methods in Enzymology 68:473 (1979), which ishereby incorporated by reference in its entirety.

Promoters vary in their “strength” (i.e., their ability to promotetranscription). For the purposes of expressing a cloned gene, it isdesirable to use strong promoters in order to obtain a high level oftranscription and, hence, expression of the gene. Depending upon thehost cell system utilized, any one of a number of suitable promoters maybe used. For instance, when cloning in E. coli, its bacteriophages, orplasmids, promoters such as the PH promoter, T7 phage promoter, lacpromoter, trp promoter, recA promoter, ribosomal RNA promoter, the P_(R)and P_(L) promoters of coliphage lambda and others, including but notlimited, to lacUV5, ompF, bla, lpp, and the like, may be used to directhigh levels of transcription of adjacent DNA segments. Additionally, ahybrid trp-lacUV5 (tac) promoter or other E. coli promoters produced byrecombinant DNA or other synthetic DNA techniques may be used to providefor transcription of the inserted gene.

Bacterial host cell strains and expression vectors may be chosen whichinhibit the action of the promoter unless specifically induced. Incertain operons, the addition of specific inducers is necessary forefficient transcription of the inserted DNA. For example, the lac operonis induced by the addition of lactose or IPTG(isopropylthio-beta-D-galactoside). A variety of other operons, such astrp, pro, etc., are under different controls.

Specific initiation signals are also required for efficient genetranscription and translation in prokaryotic cells. These transcriptionand translation initiation signals may vary in “strength” as measured bythe quantity of gene specific messenger RNA and protein synthesized,respectively. The DNA expression vector, which contains a promoter, mayalso contain any combination of various “strong” transcription and/ortranslation initiation signals. For instance, efficient translation inE. coli requires a Shine-Dalgarno (“SD”) sequence about 7-9 bases 5′ tothe initiation codon (ATG) to provide a ribosome binding site. Thus, anySD-ATG combination that can be utilized by host cell ribosomes may beemployed. Such combinations include but are not limited to the SD-ATGcombination from the cro gene or the N gene of coliphage lambda, or fromthe E. coli tryptophan E, D, C, B or A genes. Additionally, any SD-ATGcombination produced by recombinant DNA or other techniques involvingincorporation of synthetic nucleotides may be used.

Depending on the vector system and host utilized, any number of suitabletranscription and/or translation elements, including constitutive,inducible, and repressible promoters, as well as minimal 5′ promoterelements may be used.

The nucleic acid, a promoter molecule of choice, a suitable 3′regulatory region, and if desired, a reporter gene, are incorporatedinto a vector-expression system of choice to prepare a nucleic acidconstruct using standard cloning procedures known in the art, such asdescribed by Sambrook et al., Molecular Cloning: A Laboratory Manual,Third Edition, Cold Spring Harbor: Cold Spring Harbor Laboratory Press,New York (2001), which is hereby incorporated by reference in itsentirety.

The nucleic acid molecule encoding a derivative of a Clostridialneurotoxin is inserted into a vector in the sense (i.e., 5′→3′)direction, such that the open reading frame is properly oriented for theexpression of the encoded propeptide under the control of a promoter ofchoice. Single or multiple nucleic acids may be ligated into anappropriate vector in this way, under the control of a suitablepromoter, to prepare a nucleic acid construct.

Once the isolated nucleic acid molecule encoding the propeptide has beeninserted into an expression vector, it is ready to be incorporated intoa host cell. Recombinant molecules can be introduced into cells viatransformation, particularly transduction, conjugation, lipofection,protoplast fusion, mobilization, particle bombardment, orelectroporation. The DNA sequences are incorporated into the host cellusing standard cloning procedures known in the art, as described bySambrook et al., Molecular Cloning: A Laboratory Manual, Second Edition,Cold Springs Laboratory, Cold Springs Harbor, N.Y. (1989), which ishereby incorporated by reference in its entirety. Suitable hostsinclude, but are not limited to, bacteria, virus, yeast, fungi,mammalian cells, insect cells, plant cells, and the like. Preferablehost cells of the present invention include, but are not limited to,Escherichia coli, insect cells, and Pichia pastoris cells.

Typically, an antibiotic or other compound useful for selective growthof the transformed cells only is added as a supplement to the media. Thecompound to be used will be dictated by the selectable marker elementpresent in the plasmid with which the host cell was transformed.Suitable genes are those which confer resistance to gentamycin, G418,hygromycin, puromycin, streptomycin, spectinomycin, tetracycline,chloramphenicol, and the like. Similarly, “reporter genes” which encodeenzymes providing for production of an identifiable compound, or othermarkers which indicate relevant information regarding the outcome ofgene delivery, are suitable. For example, various luminescent orphosphorescent reporter genes are also appropriate, such that thepresence of the heterologous gene may be ascertained visually.

In carrying out the method of the present invention, contacting asubject with the isolated, physiologically active, atoxic derivative ofa Clostridal neurotoxin can be carried out by administering the isolatedderivative of a Clostridial neurotoxin to a subject inhalationally,parenterally, for example, subcutaneously, intravenously,intramuscularly, intraperitoneally, by intranasal instillation, or byapplication to mucous membranes, such as, that of the nose, throat, andbronchial tubes. The neurotoxin derivative may be administered alone orwith suitable pharmaceutical carriers, and can be in solid or liquidform such as, tablets, capsules, powders, solutions, suspensions, oremulsions.

The neurotoxin derivative may be orally administered, for example, withan inert diluent, or with an assimilable edible carrier, or may beenclosed in hard or soft shell capsules, or may be compressed intotablets, or may be incorporated directly with the food of the diet. Fororal therapeutic administration, the neurotoxin derivative may beincorporated with excipients and used in the form of tablets, capsules,elixirs, suspensions, syrups, and the like. In one embodiment, theformulation includes hemagglutinin proteins similar to those produced byClostridium species to protect the neurotoxin in the gastrointestinaltract. Such compositions and preparations should contain at least 0.1%of active compound. The percentage of the compound in these compositionsmay, of course, be varied and may conveniently be between about 2% toabout 60% of the weight of the unit. The amount of active compound insuch therapeutically useful compositions is such that a suitable dosagewill be obtained.

The tablets, capsules, and the like may also contain a binder such asgum tragacanth, acacia, corn starch, or gelatin; excipients such asdicalcium phosphate; a disintegrating agent such as corn starch, potatostarch, alginic acid; a lubricant such as magnesium stearate; and asweetening agent such as sucrose, lactose, or saccharin. When the dosageunit form is a capsule, it may contain, in addition to materials of theabove type, a liquid carrier, such as a fatty oil.

Various other materials may be present as coatings or to modify thephysical form of the dosage unit. For instance, tablets may be coatedwith shellac, sugar, or both. A syrup may contain, in addition to activeingredient, sucrose as a sweetening agent, methyl and propylparabens aspreservatives, a dye, and flavoring such as cherry or orange flavor.

The neurotoxin derivative may also be administered parenterally.Solutions or suspensions can be prepared in water suitably mixed with asurfactant, such as hydroxypropylcellulose. Dispersions can also beprepared in glycerol, liquid polyethylene glycols, and mixtures thereofin oils. Illustrative oils are those of petroleum, animal, vegetable, orsynthetic origin, for example, peanut oil, soybean oil, or mineral oil.In general, water, saline, aqueous dextrose and related sugar solution,and glycols such as, propylene glycol or polyethylene glycol, arepreferred liquid carriers, particularly for injectable solutions. Underordinary conditions of storage and use, these preparations contain apreservative to prevent the growth of microorganisms.

The pharmaceutical forms suitable for injectable use include sterileaqueous solutions or dispersions and sterile powders for theextemporaneous preparation of sterile injectable solutions ordispersions. In all cases, the form must be sterile and must be fluid tothe extent that syringability is possible. It must be stable under theconditions of manufacture and storage and can be preserved against thecontaminating action of microorganisms, such as bacteria and fungi. Thecarrier can be a solvent or dispersion medium containing, for example,water, ethanol, polyol (e.g., glycerol, propylene glycol, and liquidpolyethylene glycol), vegetable oils, hyaluronic acid, and suitablemixtures thereof.

The neurotoxin derivative may also be administered directly to theairways in the form of an aerosol. For use as aerosols, the neurotoxinderivative in solution or suspension may be packaged in a pressurizedaerosol container together with suitable propellants, for example,hydrocarbon propellants like propane, butane, or isobutane withconventional adjuvants. The neurotoxin derivative also may beadministered in a non-pressurized form such as in a nebulizer oratomizer.

BoNTs pass across epithelial surfaces without being destroyed or causinglocal toxicity. Passage across epithelia is believed to occur byspecific binding and transcytosis. The ability of intact BoNT A to passthough pulmonary epithelia and resist proteolytic inactivation wasdemonstrated in rat primary alveolar epithelial cells and inimmortalized human pulmonary adenocarcinoma (Calu-3) cells. The rate oftransport was greater in the apical-to-basolateral direction than in thebasolateral-to-apical direction, and it was blocked by serotype-specifictoxin antibodies (Park et al., “Inhalational Poisoning by BotulinumToxin and Inhalation Vaccination with Its Heavy-Chain Component,”Infect. Immun. 71:1147-1154 (2003), which is hereby incorporated byreference in its entirety).

Targeting the CNS may require intra-thecal or intra-ventricularadministration. Administration may occur directly to the CNS.Alternatively, administration to the CNS may involve retrogradetransport from peripheral neurons (motor neurons, nociceptors) to spinalganglia (see Caleo et al., “A Reappraisal of the Central Effects ofBotulinum Neurotoxin Type A: By What Mechanism?” Journal ofNeurochemistry 109:15-24 (2009), which is hereby incorporated byreference in its entirety).

Derivatives of a Clostridial neurotoxin of the present invention can beused to augment the endogenous pharmaceutical activity of wild typeClostridial neurotoxins (e.g., BOTOX®), e.g., as a combination therapy.

Derivatives of a Clostridial neurotoxin can be administered as aconjugate with a pharmaceutically acceptable water-soluble polymermoiety. By way of example, a polyethylene glycol conjugate is useful toincrease the circulating half-life of the treatment compound, and toreduce the immunogenicity of the molecule. Specific PEG conjugates aredescribed in U.S. Patent Application Publ. No. 2006/0074200 to Daugs etal., which is hereby incorporated by reference in its entirety. Otherconjugates include HA, which are described in U.S. Pat. No. 7,879,341 toTaylor and U.S. Patent Application Publication No. 2012/0141532 toBlanda et al., each of which is hereby incorporated by reference in itsentirety. Liquid forms, including liposome-encapsulated formulations,are illustrated by injectable solutions and suspensions. Exemplary solidforms include capsules, tablets, and controlled-release forms, such as aminiosmotic pump or an implant. Other dosage forms can be devised bythose skilled in the art, as shown, for example, by Ansel and Popovich,Pharmaceutical Dosage Forms and Drug Delivery Systems, 5^(th) Edition(Lea & Febiger 1990), Gennaro (ed.), Remington's PharmaceuticalSciences, 19^(th) Edition (Mack Publishing Company 1995), and by Ranadeand Hollinger, Drug Delivery Systems (CRC Press 1996), each of which ishereby incorporated by reference in its entirety.

According to one embodiment, by treatment it is meant dermatologic oraesthetic treatment (see e.g., Carruthers et al., “Botulinum Toxin A inthe Mid and Lower Face and Neck,” Dermatol. Clin. 22:151-158 (2004);Lang, “History and Uses of BOTOX (Botulinum Toxin Type A),” LippincottsCase Manag. 9:109-112 (2004); Naumann et al., “Safety of Botulinum ToxinType A: A Systematic Review and Meta-Analysis,” Curr. Med. Res. Opin.20:981-990 (2004); Vartanian et al., “Facial Rejuvenation UsingBotulinum Toxin A: Review and Updates,” Facial Plast. Surg. 20:11-19(2004), which are hereby incorporated by reference in their entirety) aswell as therapeutic treatment (see e.g., Bentsianov et al., “NoncosmeticUses of Botulinum Toxin,” Clin. Dermatol. 22:82-88 (2004); Carruthers etal., “Botox: Beyond Wrinkles,” Clin. Dermatol. 22:89-93 (2004);Jankovic, “Botulinum Toxin In Clinical Practice,” J. Neurol. Neurosurg.Psychiatry 75:951-957 (2004); Klein, “The Therapeutic Potential ofBotulinum Toxin,” Dermatol. Surg. 30:452-455 (2004); Schurch, “The Roleof Botulinum Toxin in Neurology,” Drugs Today (Banc) 40:205-212 (2004),which are hereby incorporated by reference in their entirety).

Subjects to be treated pursuant to the method of the present inventioninclude, without limitation, human and non-human primates, or otheranimals such as dog, cat, horse, cow, goat, sheep, rabbit, or rodent(e.g., mouse or rat).

Preferred treatment methods of the present invention include, but arenot limited to, dermatologic or aesthetic treatment, gastroenterologictreatment, genitourinaric treatment, neurologic treatment, oncologicaltreatment, and/or the treatment of any condition characterized bysynaptopathology (see, e.g., Brose et al., “Synaptopathies: Dysfunctionof Synaptic Function,” Biochem. Soc. Trans. 38:443-444 (2010); Yu & Lu,“Synapses and Dendritic Spines as Pathogenic Targets in Alzherimer'sDisease,” Neural Plasticity 2012:1-8 (2012); Siskova et al., “ReactiveHypertrophy of Synaptic Varicosities Within the Hippocampus ofPrion-Infected Mice,” Biochem Soc. Trans. 38:471-475 (2010); Warner etal., “TorsinA and DYT1 Dystonia: A Synaptopathy?” Biochem. Soc. Trans.38:452-456 (2010); Rozas et al., “Presynaptic Dysfunction inHuntington's Disease,” Biochem Soc. Trans. 38:488-492 (2010); and Jones,“Errant Ensembles: Dysfunctional Neuronal Network Dynamics inSchizophrenia,” Biochem. Soc. Trans. 38:516-521 (2010), which are herebyincorporated by reference in their entirety). Treatment of a conditioncharacterized by synaptopathology may involve the neuromodulation of thesynapse by the neurotoxin derivative.

Dermatologic or aesthetic treatment includes, but is not limited to,treatment for Rhtyiddess (wrinkles) (Sadick et al., “Comparison ofBotulinum Toxins A and B in the Treatment of Facial Rhytides,” Dermatol.Clin. 22:221-226 (2004), which is hereby incorporated by reference inits entirety), including glabellar (Carruthers et al., “Botulinum Toxintype A for the Treatment of Glabellar Rhytides,” Dermatol. Clin.22:137-144 (2004); Ozsoy et al., “Two-Plane Injection of BotulinumExotoxin A in Glabellar Frown Lines,” Aesthetic Plast. Surg. 28:114-115(2004); which are hereby incorporated by reference in their entirety),neck lines (Brandt et al., “Botulinum Toxin for the Treatment of NeckLines and Neck Bands,” Dermatol. Clin. 22:159-166 (2004), which ishereby incorporated by reference in its entirety), crows feet (Levy etal., “Botulinum Toxin A: A 9-Month Clinical and 3D In Vivo ProfilometricCrow's Feet Wrinkle Formation Study,” J. Cosmet. Laser Ther. 6:16-20(2004), which is hereby incorporated by reference in its entirety), andbrow contour (Chen et al., “Altering Brow Contour with Botulinum Toxin,”Facial Plast. Surg. Clin. North Am. 11:457-464 (2003), which is herebyincorporated by reference in its entirety). Other dermatologic treatmentincludes treatment for hypertrophic masateer muscles (Ahn et al.,“Botulinum Toxin for Masseter Reduction in Asian Patients,” Arch. FacialPlast. Surg. 6:188-191 (2004), which is hereby incorporated by referencein its entirety) and focal hyperhydrosis (Glogau, “Treatment ofHyperhidrosis with Botulinum Toxin,” Dermatol. Clin. 22:177-185, vii(2004), which is hereby incorporated by reference in its entirety),including axillary (“Botulinum Toxin (Botox) for AxillaryHyperhidrosis,” Med Lett. Drugs Ther. 46:76 (2004), which is herebyincorporated by reference in its entirety) and genital (Lee et al., “ACase of Foul Genital Odor Treated with Botulinum Toxin A,” Dermatol.Surg. 30:1233-1235 (2004), which is hereby incorporated by reference inits entirety).

Gastroentologic treatment includes, but is not limited to, treatment foresophageal motility disorders (Achem, “Treatment of Spastic EsophagealMotility Disorders,” Gastroenterol. Clin. North Am. 33:107-124 (2004),which is hereby incorporated by reference in its entirety),pharyngeal-esophageal spasm (Bayles et al., “Operative Prevention andManagement of Voice-Limiting Pharyngoesophageal Spasm,” Otolaryngol.Clin. North Am. 37:547-558 (2004); Chao et al., “Management ofPharyngoesophageal Spasm with Botox,” Otolaryngol. Clin. North Am.37:559-566 (2004), which are hereby incorporated by reference in theirentirety), and anal fissure (Brisinda et al., “Botulinum Neurotoxin toTreat Chronic Anal Fissure: Results of a Randomized ‘Botox vs. Dysport’Controlled Trial,” Ailment Pharmacol. Ther. 19:695-701 (2004); Jost etal., “Botulinum Toxin A in Anal Fissure: Why Does it Work?” Dis. ColonRectum 47:257-258 (2004), which are hereby incorporated by reference intheir entirety).

Genitourinaric treatment includes, but is not limited to, treatment forneurogenic dysfunction of the urinary tract (“Botulinic Toxin inPatients with Neurogenic Dysfunction of the Lower Urinary Tracts,”Urologia July-August:44-48 (2004); Giannantoni et al., “IntravesicalResiniferatoxin Versus Botulinum-A Toxin Injections for NeurogenicDetrusor Overactivity: A Prospective Randomized Study,” J. Urol.172:240-243 (2004); Reitz et al., “Intravesical Therapy Options forNeurogenic Detrusor Overactivity,” Spinal Cord 42:267-272 (2004), whichare hereby incorporated by reference in their entirety), overactivebladder (Cruz, “Mechanisms Involved in New Therapies for OveractiveBladder,” Urology 63:65-73 (2004), which is hereby incorporated byreference in its entirety), and neuromodulation of urinary urgeincontinence (Abrams, “The Role of Neuromodulation in the Management ofUrinary Urge Incontinence,” BJU Int. 93:1116 (2004), which is herebyincorporated by reference in its entirety).

Neurologic treatment includes, but is not limited to, treatment fortourettes syndrome (Porta et al., “Treatment of Phonic Tics in Patientswith Tourette's Syndrome Using Botulinum Toxin Type A,” Neurol. Sci.24:420-423 (2004), which is hereby incorporated by reference in itsentirety) and focal muscle spasticity or dystonias (MacKinnon et al.,“Corticospinal Excitability Accompanying Ballistic Wrist Movements inPrimary Dystonia,” Mov. Disord. 19:273-284 (2004), which is herebyincorporated by reference in its entirety), including, but not limitedto, treatment for cervical dystonia (Haussermann et al., “Long-TermFollow-Up of Cervical Dystonia Patients Treated with Botulinum Toxin A,”Mov. Disord. 19:303-308 (2004), which is hereby incorporated byreference in its entirety), primary blepharospasm (Defazio et al.,“Primary Blepharospasm: Diagnosis and Management,” Drugs 64:237-244(2004), which is hereby incorporated by reference in its entirety),hemifacial spasm, post-stroke (Bakheit, “Optimising the Methods ofEvaluation of the Effectiveness of Botulinum Toxin Treatment ofPost-Stroke Muscle Spasticity,” J. Neurol. Neurosurg. Psychiatry75:665-666 (2004), which is hereby incorporated by reference in itsentirety), spasmodic dysphonia (Bender et al., “Speech Intelligibilityin Severe Adductor Spasmodic Dysphonia,” J Speech Lang. Hear Res.47:21-32 (2004), which is hereby incorporated by reference in itsentirety), facial nerve disorders (Finn, “Botulinum Toxin Type A:Fine-Tuning Treatment of Facial Nerve Injury,” J Drugs Dermatol.3:133-137 (2004), which is hereby incorporated by reference in itsentirety), and Rasmussen syndrome (Lozsadi et al., “Botulinum Toxin AImproves Involuntary Limb Movements in Rasmussen Syndrome,” Neurology62:1233-1234 (2004), which is hereby incorporated by reference in itsentirety). Other neurologic treatments include treatment for amputationpain (Kern et al., “Effects of Botulinum Toxin Type B on Stump Pain andInvoluntary Movements of the Stump,” Am. J. Phys. Med. Rehabil.83:396-399 (2004), which is hereby incorporated by reference in itsentirety), voice tremor (Adler et al., “Botulinum Toxin Type A forTreating Voice Tremor,” Arch. Neurol. 61:1416-1420 (2004), which ishereby incorporated by reference in its entirety), crocodile tearsyndrome (Kyrmizakis et al., “The Use of Botulinum Toxin Type A in theTreatment of Frey and Crocodile Tears Syndrome,” J. Oral Maxillofac.Surg. 62:840-844 (2004), which is hereby incorporated by reference inits entirety), marginal mandibular nerve paralysis, pain control, andanti-nociceptive effects (Cui et al., “Subcutaneous Administration ofBotulinum Toxin A Reduces Formalin-Induced Pain,” Pain 107:125-133(2004) and U.S. Patent Application Publication No. 2012/0064059 toFoster et al., which are hereby incorporated by reference in itsentirety), including but not limited to pain after mastectomy (Layeequeet al., “Botulinum Toxin Infiltration for Pain Control After Mastectomyand Expander Reconstruction,” Ann. Surg. 240:608-613 (2004), which ishereby incorporated by reference in its entirety) and chest pain ofesophageal origin (Schumulson et al., “Current and Future Treatment ofChest Pain of Presumed Esophageal Origin,” Gastroenterol. Clin. NorthAm. 33:93-105 (2004), which is hereby incorporated by reference in itsentirety). Another neurologic treatment amenable to the methods of thepresent invention is headache (Blumenfeld et al., “Botulinum Neurotoxinfor the Treatment of Migraine and Other Primary Headache Disorders,”Dermatol. Clin. 22:167-175 (2004), which is hereby incorporated byreference in its entirety).

The method of the present invention is also suitable for treatment ofcerebral palsy (Balkrishnan et al., “Longitudinal Examination of HealthOutcomes Associated with Botulinum Toxin Use in Children with CerebralPalsy,” J. Surg. Orthop. Adv. 13:76-80 (2004); Berweck et al., “Use ofBotulinum Toxin in Pediatric Spasticity (Cerebral Palsy),” Mov. Disord.19:S162-S167 (2004); Pidcock, “The Emerging Role of TherapeuticBotulinum Toxin in the Treatment of Cerebral Palsy,” J. Pediatr.145:S33-S35 (2004), which are hereby incorporated by reference in theirentirety), hip adductor muscle dysfunction in multiple sclerosis (Wisselet al., “Botulinum Toxin Treatment of Hip Adductor Spasticity inMultiple Sclerosis,” Wien Klin Wochesnchr 4:20-24 (2001), which ishereby incorporated by reference in its entirety), neurogenic pain andinflammation, including arthritis, iatrogenic parotid sialocele(Capaccio et al., “Diagnosis and Therapeutic Management of IatrogenicParotid Sialocele,” Ann. Otol. Rhinol. Laryngol. 113:562-564 (2004),which is hereby incorporated by reference in its entirety), and chronicTMJ pain and displacement (Aquilina et al., “Reduction of a ChronicBilateral Temporomandibular Joint Dislocation with IntermaxillaryFixation and Botulinum Toxin A,” Br. J. Oral Maxillofac. Surg.42:272-273 (2004), which is hereby incorporated by reference in itsentirety). Other conditions that can be treated by local controlleddelivery of pharmaceutically active neurotoxin derivatives includeintra-articular administration for the treatment of arthritic conditions(Mahowald et al., “Long Term Effects of Intra-Articular BoNT A forRefractory Joint Pain,” Annual Meeting of the American College ofRheumatology (2004), which is hereby incorporated by reference in itsentirety), and local administration for the treatment of jointcontracture (Russman et al., “Cerebral Palsy: A Rational Approach to aTreatment Protocol, and the Role of Botulinum Toxin in Treatment,”Muscle Nerve Suppl. 6: S181-S193 (1997); Pucinelli et al., “BotulinicToxin for the Rehabilitation of Osteoarthritis Fixed-Flexion KneeDeformity,” Annual Meeting of the Osteoarthitis Research SocietyInternational (2004), which are hereby incorporated by reference intheir entirety). The methods of the present invention are also suitablefor the treatment of pain associated with various conditionscharacterized by the sensitization of nociceptors and their associatedclinical syndromes, as described in Bach-Rojecky et al.,“Antinociceptive Effect of Botulinum Toxin Type A In Rat Model ofCarrageenan and Capsaicin Induced Pain,” Croat. Med. J. 46:201-208(2005); Aoki, “Evidence for Antinociceptive Activity of Botulinum ToxinType A in Pain Management,” Headache 43 Suppl 1:59-15 (2003); Kramer etal., “Botulinum Toxin A Reduces Neurogenic Flare But Has Almost NoEffect on Pain and Hyperalgesia in Human Skin,” J. Neurol. 250:188-193(2003); Blersch et al., “Botulinum Toxin A and the Cutaneous Nociceptionin Humans: A Prospective, Double-Blind, Placebo-Controlled, RandomizedStudy,” J. Neurol. Sci. 205:59-63 (2002), which are hereby incorporatedby reference in its entirety.

The neurotoxin derivatives may be customized to optimize therapeuticproperties (See e.g., Chaddock et al., “Retargeted ClostridialEndopeptidases: Inhibition of Nociceptive Neurotransmitter Release InVitro, and Antinociceptive Activity in In Vivo Models of Pain,” Mov.Disord. 8:S42-S47 (2004); Finn, “Botulinum Toxin Type A: Fine-TuningTreatment of Facial Nerve Injury,” J. Drugs Dermatol. 3:133-137 (2004);Eleopra et al., “Different Types of Botulinum Toxin in Humans,” Mov.Disord. 8:S53-S59 (2004); Flynn, “Myobloc,” Dermatol. Clin. 22:207-211(2004); and Sampaio et al., “Clinical Comparability of MarketedFormulations of Botulinum Toxin,” Mov. Disord. 8:S129-S136 (2004), whichare hereby incorporated by reference in their entirety).

The derivative of a Clostridial neurotoxin may also be used, pursuant tothe treatment method of the present invention, to treat diseasesinfluenced by activity-dependent changes in synaptic structure (e.g.,synaptopathologies) or hyperactivity of synapse forming apparatus (e.g.,tubulin polymerization), and conditions associated with theproliferation of microtubules. For example, Alzheimer's Disease,Parkinson's Disease, and neuronal cancers (of both neural and glialorigin). Other conditions that may be treated by the method of thepresent invention include conditions where the synaptic complex is adisease target.

In one embodiment, neurotoxin derivatives of the present inventionaccumulate within neuronal cytosol in higher amounts than wild-typeClostridial neurotoxin.

EXAMPLES Example 1 In-Vivo Pharmaceutical Activity Experiments for BoNTA/Ad-0

Material and Methods

An atoxic derivative of Clostridium botulinum serotype A (“BoNT A/ad”),as described in U.S. Pat. No. 7,785,606 to Ichtchenko and Band (which ishereby incorporated by reference in its entirety), was expressed asdescribed. Since this neurotoxin derivative is atoxic and does notpossess a cargo attachment peptide sequence at its N-terminus, it wasdesignated “BoNT A/ad-0,” where “ad-0” means atoxic derivative with nocargo site (0), as described herein. BoNT A/ad-0 was purified toelectrophoretic homogeneity and activated by specific protease cleavageas described in Band et al., “Recombinant Derivatives of BotulinumNeurotoxin A Engingeered for Trafficking Studies and Neuronal Delivery,”Protein Expression & Purification 71:62 (2010), which is herebyincorporated by reference in its entirety. The purified protein wasprepared as a stock at a concentration of 10 mg/ml in PBS containing 40%glycerol for stabilization. The studies described below, evaluate therecombinant molecule's toxicity and pharmacologic activity.

Animals

Mice: female Balb/C mice, 5 to 7 weeks old; weight around 19+/−3 grams.

Digit Abduction Score (DAS) Assay

A modification of the classic mouse Digit Abduction Scoring (“DAS”)assay was used to determine local pharmacologic activity in muscle,measured by muscle weakening effectiveness, as described in Aoki,“Preclinical Update on BOTOX® (Botulinum Toxin Type A)-PurifiedNeurotoxin Complex Relative to Other Botulinum Neurotoxin Preparations,”European Journal of Neurology (1999), which is hereby incorporated byreference in its entirety. In the DAS Assay, mice are suspended by theirtails briefly to elicit a characteristic startle response in which theanimal extends its hind limbs and abducts its hind digits. The DAS assayis especially useful to compare the muscle weakening effectiveness ofdifferent BoNT preparations (Aoki, “Preclinical Update on BOTOX®(Botulinum Toxin Type A)-Purified Neurotoxin Complex Relative to OtherBotulinum Neurotoxin Preparations,” European Journal of Neurology (1999)and Aoki, “A Comparison of the Safety Margins of Botulinum NeurotoxinSerotypes A, B, and F In Mice,” Toxicon 39:1815-1820 (2001), which arehereby incorporated by reference in their entirety).

This test was utilized to define pharmacological activity of BoNT A/ad-0in mice. Mice were scored as having a positive DAS response when theywere unable to fully extend all digits on the injected leg. A negativescore is given to mice that spread the toes of the injected legcomparable to that of the non-injected leg.

Female Balb/C mice were given unilateral gastrocnemius intramuscularinjections with the concentration described in a volume of 3 μl of 0.9%NaCl using a 25 μl Hamilton syringe. Muscle weakness was assessed fromday 1 until 5 days post injection by suspending the mice in order toelicit a characteristic startle response and observing whether the toeson the injected leg were spreading compared to the non injected leg.

Measuring Paralysis

Definitive paralysis is described using two independent variables.First, the inability to use the injected leg to walk (paralysis); andsecond, the inability to spread the toes on the injected leg (digitalabduction).

Results: Toxicity, LD₅₀

The BoNT A/ad-0 preparation described above was used for the followingtoxicity study. The study was designed to approximate the standardmurine LD₅₀ test for wild type BoNT A (“wt BoNT A”).

A total of 30 female mice were used in this study. Each mouse wasinjected intraperitoneally with the indicated dose of BoNT A/ad-0 in 200μl of PBS (Table 1), and observed for 24 hours.

Doses ranging from 0.5 μg/mouse to 2 μg/mouse, based on the LD₅₀published by Pellett et al., “Neuronal Targeting, Internalization, andBiological Activity of a Recombinant Atoxic Derivative of BotulinumNeurotoxin A,” Biochemical & Biophysical Research Communications405(4):673-677 (2011), which is hereby incorporated by reference in itsentirety), using BoNT A/ad (1.2 μg per mouse or 50 μg/kg body weight.The LD₅₀ for BoNT A/ad-0 was found to be very similar to that for BoNTA/ad (Table 1). Briefly, 50% or 5 out of 10 mice injected with a dose of50 μg/kg body weight showed symptoms of botulism intoxication by 36hours. All mice injected with a dose of 2 μg, which is approximately83.3 μg/kg body weight, expired within 48 hours. From this study it isconcluded that 50 μg/kg body weight is the approximate LD₅₀ of BoNTA/ad-0.

TABLE 1 Results of Toxicity (LD50) Study for BoNT A/ad-0 Injected DoseNo. Mice Dead Survive   2 μg 10 10 0 1.2 μg 10 5 5   1 μg 5 1 4 0.5 μg 50 5

The LD₅₀ of wt BoNT A is approximately 0.5 ng/kg (Aoki, “A Comparison ofthe Safety Margins of Botulinum Neurotoxin Serotypes A, B, and F InMice,” Toxicon 39:1815-1820 (2001), which is hereby incorporated byreference in its entirety), or 100,000-fold lower than that of BoNTA/ad-O. Because of this toxicity, the effectiveness of wt BoNT A atextremely low doses, and the variability in potency for BoNTs producedfrom a wild type bacterial source, pharmacological doses of wt BoNT Aare generally specified in terms of “activity units,” with 1 mouse LD₅₀of wt BoNT A considered to be 1 activity unit, or approximately 0.5ng/kg of wt BoNT A (Aoki, “A Comparison of the Safety Margins ofBotulinum Neurotoxin Serotypes A, B, and F In Mice,” Toxicon39:1815-1820 (2001), which is hereby incorporated by reference in itsentirety). This takes into account concentration variations in the levelof active toxin between preparations and manufacturers. Harmonizedstandards across producers remain undefined. This is due to bothdifferent manufacturing methods and batch-to-batch variation, but isalso related to marketing claims. The final pharmaceutical preparationsare formulated with albumin (BOTOX) and/or lactose (Dysport®). From theLD₅₀ results described here, it can be concluded that 1 LD₅₀ Unit (1 U)of BoNT A/ad-0 corresponds to a dose of approximately 50 μg/kg, orapproximately 1.2 μg per mouse.

Results: Muscle Paralysis Study/DAS Assay for Pharmacologic Activity InVivo

BoNT A/ad-0 described above was tested in the murine DAS to determine ifBoNT A/ad-0 possesses pharmacological activity at doses significantlybelow its LD₅₀, and whether it displays typical dose-response activity.Mice were injected in the gastrocnemius muscle with 3 μl of BoNT A/ad-0in 0.9% NaCl using a 25 μl Hamilton Syringe. The doses administered areexpressed as the μg administered per mouse, or units of BoNT A/ad-0activity administered per mouse (Table 2).

Two observations are noted to categorize a mouse as positive for muscleparalysis induced by administration of BoNT A/ad-O. First, by theinability of the mouse to use the injected leg to walk (muscleparalysis). Second, by observing whether the digits on the injected legappeared collapsed (digital abduction). Definite muscle paralysis wasinitially observed and recorded 24 hours after the initialadministration. Mice were daily evaluated for definitive muscleparalysis for a maximum of 5 days.

The results of this pharmacologic study of BoNT A/ad-0 are shown inTable 2 and FIG. 2. Mice administered doses ranging from 0.008 LD₅₀units (0.01 μg) to 0.42 LD₅₀ units (0.5 μg) of BoNT A/ad-0 showeddefinitive muscle paralysis and digital abduction (FIG. 2 and Table 2),without any signs of mortality. In fact, 4 out of 5 animals injectedwith 0.01 μg presented with muscle paralysis and some degree of digitalabduction (Table 2), indicating that the ED₅₀ for BoNT A/ad-0, thelowest dose at which 50% of the injected animals demonstrate theintended pharmacologic activity, is 0.01 μg or lower, which correspondsto 0.008 LD₅₀ units or lower. All mice that presented paralysis on day 1continued to present paralysis to the end of the study, day 5. No signsof systemic toxicity were observed in any of the mice in this study.

These data confirm that BoNT A/ad-0 has similar pharmaceuticalproperties compared to wt BoNT A, albeit with a dose-response profile, asignificantly increased range of safe therapeutic activity and,therefore, an improved therapeutic index, and an improved safety margin.This comparison of BoNT A/ad-0 to pharmaceutical preparations of wt BoNTis illustrated in Table 3, and contrasted to the data reported by Aoki,“A Comparison of the Safety Margins of Botulinum Neurotoxin Serotypes A,B, and F In Mice,” Toxicon 39:1815-1820 (2001), which is herebyincorporated by reference in its entirety. For instance, Aoki, “AComparison of the Safety Margins of Botulinum Neurotoxin Serotypes A, B,and F In Mice,” Toxicon 39:1815-1820 (2001), which is herebyincorporated by reference in its entirety, reported that the safetymargin for BOTOX® is about 13.9+/−1.7 and for Dysport® 7.6+/−0.9. Hereit is shown that at the lowest dose of BoNT A/ad-0 studied, 0.01 μg,definite paralysisis was observed in 4/5 mice. This dose can beconsidered a conservative estimate of the ED₅₀. Therefore, for BoNTA/ad-0, the safety margin is approximately 120, or expresseddifferently, approximately 10-fold better that that for BOTOX® orDysport® (Table 3).

TABLE 2 Results of Pharmacologic Study of BoNT A/ad-0 No. with Dose LD₅₀No. Definitive No. Injected per Mouse Units Mice Paralysis Dead 0(placebo) 0 9 0 0 0.01 μg  0.008 5 4 0 0.1 μg 0.08 5 5 0 0.5 μg 0.42 1010 0   1 μg 0.83 5 5 0 1.2 μg 1 5 2 3 1.5 μg 1.25 5 1 4

Naive mice were administered BoNT A/ad-0 in the left gastrocnemius viaintramuscular injection with 3 μl containing the indicated mass or unitsof BoNT A/ad-O.

TABLE 3 LD50 and ED50 of BoNT A/ad-0 LD₅₀ = ~1.2 μg ED₅₀ = ~0.01 ug(ED₅₀ = 0.01 μg or lower) LD₅₀/ED₅₀ = safety margin = ~120

If expressed as units, the ED₅₀ of BoNT A/ad-0 is 0.008 LD₅₀ units, orlower.

Comparison to Prior Studies and Conclusions

Prior studies have found that mutations introduced into the light chainof recombinant BoNT A/ad (a molecule containing a cargo attachmentpeptide as described in U.S. Patent Application Publication No.2011/0206616 to Ichtchenko and Band, which is hereby incorporated byreference in its entirety) increased the LD₅₀ of the toxin by100,000-fold. In particular, injections of 0.5 μg (n=25) or 1 μg (n=15)of BoNT A/ad (in the absence of any therapeutic agent) were made intothe tibialis muscle two months prior to administration of the repeatdose to each animal. The repeat dose, consisting of 3 μl containing theindicated quantitites of BoNT A/ad, 1 μg (n=18) or 2 μg (n=20), weresimilarly injected into the tibialis muscle. These data (Table 4 andTable 5) suggest that immune resistance to BoNT A/ad is not developingwith repeat treatment.

TABLE 4 BoNT A/ad Induces Paralysis No. with Definitive No. Dead (withinDose No. Mice Paralysis 48 hrs) 0 (placebo) 21 0 0 0.5 μg 38 34 0   1 μg15 12 1 1.2 μg 10 5 51.2 μg is the apparent LD₅₀ for intramuscular injections of BoNT A/adestimated from this experiment.

TABLE 5 Paralytic Effect After Re-injection of BoNT A/ad No. withDefinitive No. Dead (within Repeat Dose No. Mice Paralysis 48 hrs) 1 μg18 17 0 2 μg 20 15 dead, with 3 appearing sick. 2 mice appeared normalat 48 hrs.

In the present study it was found that the LD₅₀ of BoNT A/ad-0, whichhas identical toxin-disabling mutations as BoNT A/ad, is likewiseelevated ˜100,000-fold relative to wt BoNT A. But surprisingly, it wasobserved that BoNT A/ad-0 still possessed pharmacologic activity similarto that observed for wt BoNT A, and that a therapeutic agent need not bedelivered via the cargo site of BoNT/A ad to render it therapeutic. Bycomparing the dose-response of BoNT A/ad-0 to that reported forpharmaceutical preparations of wt BoNT A, it can be concluded that BoNTA/ad-0 can be used for pharmaceutical treatments in the same way as wtBoNTs, but with significantly reduced danger of systemic toxicity, andthus significant improved safety advantages for clinical use.

Although the invention has been described in detail for the purposes ofillustration, it is understood that such detail is solely for thatpurpose, and variations can be made therein by those skilled in the artwithout departing from the spirit and scope of the invention which isdefined by the following claims.

What is claimed:
 1. A treatment method comprising: contacting a subjectwith an isolated, physiologically active, atoxic derivative of aClostridial neurotoxin, said contacting being carried out to treat thesubject, with the proviso that the derivative of a Clostridialneurotoxin does not possess a cargo attachment peptide sequence at itsN-terminus.